賈森·戴利/文　陳先宇/譯

The DNA of the durian， it turns out， is very complex and optimized for producing a wretched stench1. 研究發(fā)現(xiàn)，榴蓮的DNA異常復(fù)雜，而且為了能夠產(chǎn)生惡臭而進(jìn)行了優(yōu)化。

The durian is a most confounding fruit. The outer layer of these large spiky melon-like footballs smell so bad that it is banned from public transportation and public spaces in Singapore. Food writer Richard Sterling has described it as pig poop mixed with “turpentine and onions， garnished with a gym sock.” The taste of the custardy inside， however， has garnered the potent fruit millions of fans， describing it as “hell on the outside and heaven on the inside.”

榴蓮這種水果最讓人琢磨不透。它個(gè)頭大得像甜瓜或者橄欖球，渾身帶刺，外殼氣味實(shí)在難聞，以至于新加坡禁止榴蓮出現(xiàn)在公共交通工具和公共場(chǎng)所里。美食作家理查德·斯特林曾將榴蓮比作混合了“松脂、洋蔥，再用一只運(yùn)動(dòng)襪點(diǎn)綴”的豬糞。然而，榴蓮雖然氣味濃烈，但類似蛋奶沙司的果肉細(xì)膩可口，為其圈粉無(wú)數(shù)——他們形容這種烈性水果“外表像地獄，里面是天堂”。

Whatever its love or hate， most who have encountered durian have a strong opinion about it. In an effort to unravel its stinky goodness， researchers examined the genome of this “king of fruits.” They published their results in the journal Nature Genetics.

愛(ài)也好，恨也罷，與榴蓮邂逅的人大多對(duì)其印象深刻。榴蓮號(hào)稱“水果之王”，為揭示其臭味之源，研究人員對(duì)其基因組進(jìn)行了檢測(cè)，研究結(jié)果發(fā)表于《自然·遺傳學(xué)》期刊。

There are about 30 species in the Durio genus， and the most common species， Durio zibethinus， has about 200 varieties that are bred for the market. In fact， its an important cash crop in Asia—China alone imports $600 million worth of the fruit each year. So understanding a little about its genome is important to breeding new varieties and safeguarding the species from disease.

榴蓮屬下約有30個(gè)物種，其中最常見(jiàn)的榴蓮約有200個(gè)品種是面向市場(chǎng)培育的。榴蓮其實(shí)是亞洲的重要經(jīng)濟(jì)作物，僅中國(guó)每年就進(jìn)口價(jià)值高達(dá)6億美元的榴蓮。因此，稍微了解一下榴蓮的基因組，對(duì)培育榴蓮新品種和預(yù)防榴蓮病害都非常重要。

Researchers at the National Cancer Centre in Singapore sequenced the genome of a durian variety called Musang King， one of the most delicate and popular cultivars. What they found is an extremely complex plant， with nearly 46，000 genes—about twice the number found in humans. Equally interesting， they found the stinky species shares an evolutionary ancestor with another favorite plant， cacao， which is used to make chocolate.

貓山王是最美味、最受歡迎的榴蓮栽培品種之一，新加坡國(guó)立癌癥中心的研究人員對(duì)貓山王榴蓮的基因組進(jìn)行了測(cè)序。他們發(fā)現(xiàn)，貓山王是一個(gè)極其復(fù)雜的品種，有近4.6萬(wàn)個(gè)基因，大約是人類基因數(shù)量的兩倍。同樣有趣的是，他們發(fā)現(xiàn)這個(gè)散發(fā)臭味的物種與另一種人們喜愛(ài)的植物——用于制作巧克力的可可——在進(jìn)化過(guò)程中有著共同的祖先。

But， reports Kendra Pierre-Louis at Popular Science， durians ancestors went through some radical changes once it split from cacao 65 million years ago. The genome of durian underwent a duplication event. This means that it copied the genome of its cacao ancestor and incorporated it into its DNA. That allowed the plant to continue on with its essential functions in this original set of genes， while another set began changing and mutating—such as its development of thorny skin and rank2 odor.

然而，據(jù)肯德拉·皮埃爾-路易斯在《大眾科學(xué)》雜志上發(fā)表文章稱，榴蓮的祖先自6500萬(wàn)年前與可可分離后，發(fā)生了根本性改變。榴蓮基因組經(jīng)歷了重復(fù)事件，也就是說(shuō)榴蓮復(fù)制了其祖先可可的基因組，然后將其融入自己的DNA。如此一來(lái)，榴蓮能夠繼續(xù)發(fā)揮原始基因組賦予其的基本功能，復(fù)制而來(lái)的另一組基因同時(shí)開(kāi)始改進(jìn)和突變，比如進(jìn)化出長(zhǎng)刺的外殼和難聞的氣味。

“Its almost like you cloned yourself， and you have one copy of yourself go and do the housework and cleaning and so forth so the other one can go on and do all sorts of different things，” study author Patrick Tan， researcher at Singapores Duke-NUS Medical School， tells Pierre-Louis.

研究論文作者帕特里克·陳（音譯）是杜克-新加坡國(guó)立大學(xué)醫(yī)學(xué)院的研究員。他告訴皮埃爾-路易斯：“這差不多就像你克隆了你自己。你讓其中一個(gè)你去做諸如家務(wù)活、打掃衛(wèi)生之類的事，另一個(gè)你就可以繼續(xù)做其他各種各樣的事。”

Researchers identified one of the genes the durian developed to produce its odor， which they believe is produced to attract primates， like orangutans—and humans—who disperse the seeds. The researchers found a class of genes called methionine γ-lyase （MGLs） that regulate the production of volatile sulfur compounds， which are quite stinky.

研究人員識(shí)別出了榴蓮進(jìn)化出來(lái)用于散發(fā)臭味的一個(gè)基因。他們認(rèn)為榴蓮之所以要散發(fā)臭味，是為了吸引猩猩和人類等靈長(zhǎng)類動(dòng)物來(lái)傳播自己的種子。研究人員發(fā)現(xiàn)了一種名為甲硫氨酸γ-裂解酶的基因，可以調(diào)節(jié)揮發(fā)性硫化物的產(chǎn)生，而這類硫化物相當(dāng)臭。

“We found that this gene is highly expressed only in the fruit—the pulp—but not in the leaves or the stem or the roots，” co-author Bin Tean Teh tells Genelle Weule at the Australian Broadcasting Corporation. “This gave us the first clue that this is a key gene that results in the strong， pungent smell of durian.”

“我們發(fā)現(xiàn)這種基因只在果肉中高度表達(dá)，而在葉、莖、根中并沒(méi)有?！毖芯空撐暮现哙嵜粽瓜虬拇罄麃啅V播公司的記者蓋內(nèi)爾·沃伊勒透露，“這給了我們第一條重要線索，說(shuō)明它是使榴蓮產(chǎn)生強(qiáng)烈刺鼻氣味的關(guān)鍵基因?！?/p>

Weule reports that the production of these sulfur compounds is turbocharged3 in durians. While close cousins like cacao only have one copy of the gene， durian has four versions of the stink gene， meaning the fruit is optimized for producing a primate-enticing funk—especially since those genes are only active when the fruit is ripe.

沃伊勒?qǐng)?bào)道稱，硫化物的生成在榴蓮中得到了強(qiáng)化。榴蓮近親（如可可）只有1個(gè)甲硫氨酸γ-裂解酶拷貝，而榴蓮有4個(gè)，這說(shuō)明榴蓮為了能產(chǎn)生吸引靈長(zhǎng)類動(dòng)物的臭味而進(jìn)行了優(yōu)化——特別是因?yàn)檫@些基因只在果實(shí)成熟后才發(fā)揮作用。

Thats just one element of durians odorific formula. As Joseph Stromberg wrote in 2012， researchers discovered that the fruits odor comes from 50 different compounds， including four that were new to science at the time. Another study published in 2017 found that two main compounds， one that smells fruity and one that smells like onions， give the durian most of its smell.

這只是榴蓮臭味配方中的一個(gè)成分。正如約瑟夫·斯特龍伯格在2012年所述，研究人員發(fā)現(xiàn)榴蓮的臭味來(lái)自50種化合物，其中4種是當(dāng)時(shí)科學(xué)界的新發(fā)現(xiàn)。2017年發(fā)表的另一項(xiàng)研究發(fā)現(xiàn)，榴蓮的氣味主要來(lái)自兩種化合物：一種聞起來(lái)像水果；另一種聞起來(lái)像洋蔥。

The genome research could also lead to genetic modification4 of the fruit， allowing scientists to knock out the stink gene， Teh tells Weule. But not all would welcome the change; half the fun of durian is enduring the stench while chowing down on its creamy center.

鄭敏展告訴沃伊勒，基因組研究還可能引發(fā)對(duì)榴蓮的遺傳修飾，從而使科學(xué)家能夠消除臭味基因。然而，并非所有人都樂(lè)于接受這種改變，畢竟食用榴蓮的樂(lè)趣大半在于邊忍受惡臭，邊狼吞虎咽地享用口感細(xì)膩的果肉。

（譯者為“《英語(yǔ)世界》杯”翻譯大賽獲獎(jiǎng)?wù)撸粏挝唬褐袊?guó)巨石股份有限公司）

1 stench臭味。

2 rank難聞的。? 3 turbocharge渦輪增壓，增強(qiáng)。

4遺傳修飾是通過(guò)分子生物學(xué)技術(shù)對(duì)生物體的基因組進(jìn)行改造的技術(shù)。